1. Field of the Invention
The present invention relates to a data management device which has a nonvolatile storage apparatus such as a hard disc drive, a printer, a facsimile, a copying machine, a server machine, and a personal computer; a method for managing data; and a storage medium.
Priority is claimed on Japanese Patent Application No. 2005-45239 and No. 2005-45240, filed Feb. 22, 2005, and Japanese Patent Application No. 2005-197370, filed Jul. 6, 2005 the content of which is incorporated herein by reference.
2. Description of Related Art
In printers and other devices, font data and job data which are sent from a host computer are saved in a removable hard disc (HDD). Therefore, there is a risk of data leakage when the HDD is taken away.
Conventionally, some arts for preventing data leakage described hereinbelow are known. Japanese Unexamined Patent Application, First Publication No. 2002-260326 discloses an art which scrambles video data or audio data when saved in a storage medium, using a key which is made by encrypting unique information to a reproducing device by the identifier of the storage medium. Japanese Unexamined Patent Application, First Publication No. 2003-303136 discloses an art which deletes a key after reproducing encrypted data saved in a storage medium such as a compact disc (CD). Japanese Unexamined Patent Application, First Publication No. 2003-131950 discloses an art which encrypts digitalized copyrighted works, using information unique to a device, and saves the encrypted data in a storage device such as a memory card.
However, these aforementioned arts do not have sufficient security. In addition, the data becomes useless when the key is broken because of an error in operation or for other reasons, since these arts do not consider the case in which a key for decryption is broken.